MFJ: MFJ-1278B
多模式 TNC 封包數據機
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| 規格說明
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| Processor |
CMOS Z-80A |
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Clocks |
| Processor master clock input frequency |
4.9152 MHz |
| User Port Clock |
Switch selectable at 16x baud rate |
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Memory |
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All memory in industry-standard JEDEC Byte-Wide sockets. |
| Standard complement of ROM |
1 Megabit(128K×8)
1 × 27C101 |
| Standard complement of system RAM |
32K
1×43256C-15L |
| Standard complement of mailbox RAM |
32K
1×43256C-15L(expandable to 512K) |
| Serial Port |
Z8440 SIO/0 port B configured as UART plus low-power TTL-to-RS-232C signal level interface.
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Standard female DB-25S(DCE) RS-232C connector.
8-pin TTL connector for TTL serial port. |
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Baud rates supported : 300,1200,2400,4800,9600 and 19200.
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Modem |
| Demodulator |
XR2211 PLL demodulator circuit plus related components to receive up to 1200 baud. |
| Modulator |
XR2206 modulator circuit plus related components to produce tones for all modes of operation. |
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Built-in modem calibration system.
An external modem may be attached by a single connector which completely bypasses the on-board modem.
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A Tuning Indicator is built in to be used as a tuning aid for all modes of operation. |
| bbRAM |
Non-volatile storage of all important operating parameters is accomplished by using a battery backed-up system |
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for the entire 32K bytes of system RAM and all mailbox RAM. |
| Protocol |
AX.25 Level 2 is supported.
Pre-Version 2.0 support is compatible with earlier TAPR TNCs running 3.x software. |
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Full support of Version 2.0 protocol is provided.
Full duplex radio link operation is supported. |
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Packet Operating Modes |
| Command Mode |
Accepts commands via user port. |
| Converse Mode |
Accepts digital data, transmits and receives packets, permits terminal editing features(character delete, line delete, input packet delete, |
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output packet delete and redisplay input)via special characters trapped by the MFJ-1278B. |
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Escape to command mode via special character or BREAK signal. Optional use of packet completion timer as in Transparent mode. |
| Transparent Mode |
Accepts digital data, transmits packets via packet completion timer or buffer full only,and receives packets. |
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No local editing features permitted.Escape to command mode via specially timed character sequence or BREAK signal. |
| Power Required |
+12 volts DC at 500mA. |
